1. Field of the Invention
The invention relates to a VoIP communication apparatus intervening between telephone device and call server, its number pattern correspondence storing method and its number judging method.
2. Related Background Art
In communication system, a VoIP (Voice over Internet Protocol) communication apparatus intervening between telephone device and call server is used. The VoIP communication apparatus, for example, is connected with a telephone device via telephone wire and is connected with a call server via MGCP (Media Gateway Control Protocol) on Internet. The VoIP communication apparatus may restrain the data transmission amount toward the call server.
That is, the call server previously manages all telephone numbers corresponding telephone subscribers, and has a PBX (private branch exchange) for connecting to a corresponding connection destination on the basis of a dial number output from the telephone device. When the PBX judged that the dial number does not exist in the all telephone numbers, that is, the connection destination does not exist, in order to notify the telephone device which output the dial number of such un-accurate situation, the PBX sends a signal as a data, such as voice to the telephone device. Because of this, between the telephone device and the call server, the transmission amount of round-trip data becomes much.
In order to decrease the transmission amount, it can be considered to provide the VoIP communication apparatus intervening between the telephone device and call server with a judging function to judge the accuracy of the dial number, then, to only send the dial number having accuracy to the call server.
In order to realize the judging function, the VoIP communication apparatus should receive a number pattern from the call server, which expresses a number scope obtained on the basis of each telephone number managed by the call server; then, on the basis of the number pattern, store a corresponding scope data expressing the number scope; further, by referring the scope data, judge whether the dial number received from the telephone device corresponds to the number scope, that is, whether the dial number has accuracy.
With respect to the scope data, in the past, it is obtained by changing the data of the number pattern into binary code. Because of this, in order to store the scope data with binary code, it is necessary to prepare a memory having an enormous storing amount.
However, in the VoIP communication apparatus, because the memory capacity for storing data only is small in general, it is difficult to store such scope data.